...[W]ith written proposals from both sides now on the table, senior aides say the elements of a deal are coming into focus:

• Fresh tax revenue, generated in part by raising rates on the wealthy, as Obama wants, and in part by limiting their deductions, as Republicans prefer. The top rate could be held below 39.6 percent, or the definition of the wealthy could be shifted to include those making more than $375,000 or $500,000, rather than $250,000 as Obama has proposed.

Obama wants $1.6 trillion over the next decade, but many Democrats privately say they would settle for $1.2 trillion. Boehner has offered $800 billion, and Republicans are eager to keep the final tax figure under $1 trillion, noting that a measure to raise taxes on the rich passed by the Senate this summer would generate only $831 billion.

• Savings from health and retirement programs, a concession from Democrats necessary to sell tax hikes to GOP lawmakers. Obama has proposed $350 billion in health savings over the next decade. Boehner has suggested $600 billion from health programs, and an additional $200 billion from using a stingier measure of inflation, reducing cost-of-living increases for Social Security recipients.

• Additional savings sufficient to postpone roughly $100 billion in across-the-board agency cuts set to hit in 2013, known as the sequester, and to match a debt-limit increase. The sequester, perhaps paired with an automatic tax hike, could then serve as a new deadline, probably sometime next fall, for wringing additional revenue from the tax code and more savings from entitlement programs.

For the White House, the key to any deal is tax revenues — delivered at least partly through higher rates — and a long-term solution to the debt ceiling. Additionally, any big deal will have to include some stimulus, including an extension of unemployment insurance and either an extension of — or more likely, a replacement for — the payroll tax cut.

For Republicans, the key is some give on tax rates, as well as a few high-profile entitlement cuts, namely an increase in the Medicare eligibility age and chained-CPI.

It’s by no means certain the two sides will come to a “grand bargain” before the end of the month. But if they do, the bargain will likely include either those policies outright, or instructions for Congress to work on those policies over the coming months.

But any deal will include much more than those top-line items. It will also include deficit-reduction and tax reform targets for Congress to hit in the coming months. That gets to a deeper problem in the negotiations: When you drill down to the granular policy level, Republicans aren’t sure what Republicans want. Democrats complain that the Republican offers are bare of policy detail. They lay down targets — say, $600 billion in health savings — but say nothing about how those targets will be achieved.

Republican staffers admit that they need more time to come up with specific cuts — and, for that matter, specific tax reforms. But they argue they’ll have that time. Any deal is expected to include a two-stage process: Targets for spending cuts and tax revenues now, combined with consequences that force Congress to hit those targets later.

If the White House and lawmakers fail to reach an agreement to avoid the cliff, how will the financial markets react? The Associated Press reports:

WASHINGTON — Congress and the White House can significantly soften the initial impact of the “fiscal cliff” even if they fail to reach a compromise by Dec. 31. One thing they cannot control, however, is the financial markets’ reaction, which possibly could be a panicky sell-off that triggers economic reversals worldwide.

The stock market’s unpredictability is perhaps the biggest wild card in the political showdown over the fiscal cliff.

President Barack Obama’s re-election gives him a strong negotiating hand, as Republicans are increasingly acknowledging. And some Democrats are willing to let the Dec. 31 deadline pass, because a rash of broad-based tax hikes would pressure Republicans to give more ground in renewed deficit-reduction negotiations.

A chief fear for Obama’s supporters, however, is that Wall Street would be so disgusted or dismayed that stocks would plummet before lawmakers could prove their newfound willingness to mitigate the fiscal cliff’s harshest measures, including deep, across-the-board spending cuts that Defense Secretary Leon Panetta says could significantly damage the nation’s military posture. Some Republicans believe that fear will temper the president’s insistence on a hard bargain this month. Obama and GOP House Speaker John Boehner on Sunday held their first meeting between just the two of them since the election, and spokesmen for both emphasized afterward their lines of communication remain open.

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